Only if your using the mg gauges though, if it's a digi dash then it's separate?

I think the problem here is that a few of us have good knowledge of the mg / rover wiring but we don't know how this connects to your mini loom. Agoaty has used the entire mems2 engine and body loom striped out to just what he needed, factory rover gauges, clocks and column switches etc. I have a custom closed mems3 engine loom which just needed about 5 wires to actually run. Custom made car loom that is powered from the mems3 fuse box, digi dash is separate again. I repurposed the factory grey plug and a couple of mgzr tailgate plugs to connect the engine loom to my custom car loom (starter button, ignition switch, 5as led, alternator led, coolant led, rpm, fuel pump etc etc).

If you still have the mini loom with the glass fuses you'd be best getting a closed mems3 loom made from your bits then just powering the mini from the mems3 fuse box.

I think that is the info your after ?

Indeed it is, I spent some time reviewing all the pin outs yesterday as the colors don't mean anything and one thing I have noticed is there appears to be little required from the grey plug on the engine loom? Most items required seem to be via the ecu 2 plug.

Obviously I can use the cateram diagrams for the majority of plugs but would anyone know the plugs which are the output from the fuse box based mfru? For the starter motor etc?

Starter motor is controlled by the yellow 'main relay' in the mems3 fuse box. That is controlled by the Ecu after it is unlocked via the 5as. There are lots of diagrams online of which relays are which in the fuse box but not any of the pin outs on the fuse box. Might be because cateram used their own fuse box design?

If I remember right most the plugs that go in the bottom of the mems3 fuse box are full size spade with about 3 pins each, these are power outputs for stuff like lights and abs. I just started pulling fuses and worked out what was what with the multimeter. There is a multiplug that goes in the bottom of the mems3 box that's about 12 smaller pins, that would be the one you need to get it running, wire colours should be traceable from it.

Gazwad would be able to help you further with that one. Grey plug to car body is 9 pin, only about 4 of them are needed to run, they should be on the diagram.